[For Elementary School Students] 3-Choice Quiz to Deepen Knowledge of Living Things

Only one survives

When an earthworm is torn in half, only the side with the head fully regenerates and survives. However, in the case of an earthworm called the Yamato-hime earthworm, even if it splits, each part regenerates. What’s more, as it grows, it voluntarily divides its body into about ten parts, rapidly increasing its numbers.

pancake tortoise

The pancake tortoise was given its name because its shell is flat and soft like a pancake. Pancake tortoises live in Africa, where they are locally called the crevasse tortoise. Thanks to the characteristics of their shell, they are skilled at climbing cliffs.

tuna

Tuna keep swimming even while they sleep so they can breathe and keep their bodies from sinking. Unlike humans and many other animals, they don’t get solid sleep; instead, they swim while slightly reducing their speed to conserve energy.

black

At first glance, polar bears look like they have white bodies, but their skin beneath the fur is actually black. What’s more, the fur that appears white isn’t truly white—it’s transparent, and it looks white because of the black skin underneath and the sunlight. Since the fur is transparent, it lets in plenty of sunlight, helping them retain heat very effectively!

How much

Since ikura means fish eggs in Russian, caviar—which comes from sturgeon eggs—is said to be called “black ikura.” Speaking of salmon eggs, in addition to ikura there is also sujiko. Sujiko refers to eggs that remain in the ovary membrane in clusters, while ikura refers to eggs that have been removed from the ovary and separated into individual grains.

milk

The food that pigeons give to newly hatched chicks is a special milk called 'pigeon milk' or 'crop milk.' It is produced in a sac-like organ near the pigeon's throat called the crop. Because it is highly nutritious and easy to digest, it is considered the ideal food for chicks shortly after birth. Although its composition differs from mammalian milk, the name 'crop milk' was given because the way parent birds feed it mouth-to-mouth to their chicks resembles mammals nursing their young.

Only one side moves

A crab’s claws are set up so that one side is fixed and doesn’t move, while only the other side moves. Crabs use these claws to catch food and tear it into bite-sized pieces. Incidentally, a crab’s claws are considered legs, not hands.